Retort packaging is common in the fruit juice industry where hot juices, typically at temperatures ranging from 80.degree. C. to 120.degree. C., are filled directly into the final disposable commercial packaging. By filling with hot juice, the container is simultaneously filled and sanitized. The use of polyamides as layers in such retort packaging has generally been unsuitable for a number of reasons, namely, many polyamides are crystalline in nature, lacking the level of clarity necessary for aesthetically pleasing clear containers; some polyamides lack a glass transition temperature sufficiently high enough to maintain the shape of the container and prevent deformation thereof during hot fill; and some polyamides lack the oxygen barrier properties necessary to prevent oxidation and discoloration of fruit juices held by containers made therefrom. Conventional polyamides include those set forth in NL Pat. No. 7,212,060; U.S. Pat. Nos. 4,018,746; 4,482,695; and 4,640,973; these polyamides generally suffer from either having a relatively low glass transition temperature, employing relatively high cost monomers, or exhibiting relatively low levels of clarity.
Accordingly, one object of the present invention is to provide a polyamide which has the combined properties of a high glass transition temperature, excellent clarity, and a low oxygen transmission rate.
Another object of the present invention is to provide an amorphous polyamide resin suitable as a container layer for hot filled fruit juices or other hot filled, oxygen sensitive liquids.